Removal of Dyes Using Conventional and Advanced Adsorbents Advanced Adsorbents

Abstract

Dyes are an important class of pollutants, and can even be identified by the human eye. Disposal of dyes in precious water resources must be avoided, however, and for that various treatment technologies are in use. Among various methods, adsorption occupies a prominent place in dye removal. The growing demand for efficient and low-cost treatment methods and the importance of adsorption has given rise to low-cost alternative adsorbents. This thesis work focused on liquid phase adsorptive removal of organic dyes viz. Crystal violet and Coomassie brilliant blue where they represent the class of a basic and an acid dye respectively. The adsorbents used were: MIL-53 or Fe-BDC (a known Metal Organic Framework), activated carbon and different variants of commercially available zeolites viz. 4A, 5A and 13X. The characterization of all the adsorbents were carried out using conventional techniques like scanning electron microscopy (SEM), powder X-ray diffraction analysis (PXRD), thermogravimetric analysis (TGA) and N2 adsorption analysis (BET). The results with activated carbon showed a high removal percentage (>90%) of both the dyes, irrespective of dosage concentration. The results on the other hand with zeolites were measured to be a function of its concentration. MIL-53 MOF had shown great potential in degrading the organic dyes which can be attributed to its higher percentages of active metal sites and low band gap energy (influencing photocatalysis simultaneously).